Low engagement force terminal with easy off-axis disengagement

Abstract

A low insertion force electrical contact terminal assembly in which the female terminal has multiple cantilevered arms which engage and retain the male terminal therein. The multiple cantilevered arms resist withdrawal of the male terminal along the mating axis but will readily permit withdrawal during an off-axis disengagement of the terminals.

I claim: 
     
       1. A low insertion force electrical contact terminal assembly comprising a male terminal and a female terminal, said female terminal constructed of metal and having at least two cantilevered biased arms equidistantly spaced about a central longitudinal axis, said arms being interconnected at a first end adapted for securement to an electrical conductor means, each of said arms also being independently and freely movable at a second end opposite said first end, said second end terminating in a lip cooperating to define an insertion opening in said female terminal and through which a correspondingly shaped male contact terminal is adapted to be received and engaged with interior surfaces of each of said arms upon a relatively low insertion force, each of said arms including first, second and third ramped surfaces, said first ramped surface being adjacent to said lip and angled inward toward said central axis when viewed proceeding away from said lip and toward said first end, said second ramped surface being generally adjacent to said first ramped surface and being angled outward away from said central axis when viewed proceeding from said lip and toward said first end, said third ramped surface being generally adjacent to said second ramped surface and being angled inward toward said central axis when viewed proceeding from said lip and toward said first end, said first and third ramped surfaces being angled with respect to said central axis in an amount greater than said second ramped surface, said third ramped surfaces of said arms cooperating to define a reduced diameter portion which acts to limit the distance which said male contact terminal can be inserted into said female contact terminal, the cantilevering of said arms further cooperating such that said second and third ramped surfaces provide a substantially circumferential high contact normal force against said male contact terminal thereby substantially eliminating relative movement between said female and male contact terminals and microarcing result from relative movement, the decreased angle of said second ramped surfaces cooperating with the independent deflectability of said arms to provide a decreased resistance to withdrawal of said male contact terminal from said female terminal when withdrawal is at an off-angle relative to said central axis, said male terminal including portions configured to engage said first, second and third ramped surfaces of said female terminal. 
     
     
       2. A terminal as set forth in claim 1 wherein said arms are curved in transverse cross section defining a generally circular insertion opening. 
     
     
       3. A terminal as set forth in claim 1 wherein said arms are generally angled inward toward said central axis when in a non-engaged condition with said male contact terminal. 
     
     
       4. A terminal as set forth in claim 1 wherein said arms are generally angled outward away from said central axis when in an engaged condition with said male contact terminal. 
     
     
       5. A terminal as set forth in claim 1 wherein said first ramped surface smoothly merges into said second angled surface. 
     
     
       6. A terminal as set forth in claim 1 wherein said first ramped surface is angled with respect to said central axis at an angle within the range of 20°-35°. 
     
     
       7. A terminal as set forth in claim 1 wherein said first ramped surface is angled with respect to said central axis at an angle of about 28°-29°. 
     
     
       8. A terminal as set forth in claim 1 wherein said third ramped surface is angled with respect to said central axis at an angle within the range of 25°-35°. 
     
     
       9. A terminal as set forth in claim 1 wherein said third ramped surface is angled with respect to said central axis at an angle of about 30°. 
     
     
       10. A terminal as set forth in claim 1 wherein said female terminal includes three cantileverly biased arms. 
     
     
       11. A terminal as set forth in claim 10 wherein said arms are equidistantly spaced about said central axis at approximately 120° intervals. 
     
     
       12. A terminal as set forth in claim 1 wherein said second ramped surface smoothly merges into said third angled surface. 
     
     
       13. A terminal as set forth in claim 12 wherein first ramped surface smoothly merges into said second angle surface. 
     
     
       14. A terminal as set forth in claim 1 wherein said arms having a length which is greater than the maximum width of said female terminal as defined by said arms. 
     
     
       15. A terminal as set forth in claim 14 wherein said length is less than twice the maximum width of said arms. 
     
     
       16. A terminal as set forth in claim 14 wherein said length is approximately 1.5 times the maximum width of said arms. 
     
     
       17. A terminal as set forth in claim 14 wherein said length is less than 1.5 times the maximum width of said arms. 
     
     
       18. A low insertion force electrical contact terminal comprising a female terminal constructed of metal and having at least two cantilevered biased arms equidistantly spaced about a central longitudinal axis, said arms being interconnected at a first end adapted for securement to an electrical conductor means, each of said arms also being independently and freely movable at a second end opposite said first end, said second end terminating in a lip cooperating to define an insertion opening in said female terminal and through which a correspondingly shaped male contact terminal is adapted to be received and engaged with interior surfaces of each of said arms upon a relatively low insertion force, each of said arms including first, second and third ramped surfaces, said first ramped surface being adjacent to said lip and angled inward toward said central axis when viewed proceeding away from said lip and toward said first end, said second ramped surface being generally adjacent to said first ramped surface and being angled outward away from said central axis when viewed proceeding from said lip and toward said first end, said third ramped surface being generally adjacent to said second ramped surface and being angled inward toward said central axis when viewed proceeding from said lip and toward said first end, fourth ramped surface being located between said first end and said third ramped surface and being angled away from said central axis proceeding toward said first end, said first and third ramped surfaces being angled with respect to said central axis in an amount greater than said second ramped surface, said third ramped surfaces of said arms cooperating to define a reduced diameter portion which acts to limit the distance which said male contact terminal can be inserted into said female contact terminal, the cantilevering of said arms further cooperating such that said second and third ramped surfaces provide a substantially circumferential high contact normal force against said male contact terminal thereby substantially eliminating relative movement between said female and male contact terminals and microarcing resulting from relative movement, the decreased angle of said second ramped surfaces cooperating with the independent deflectability of said arms to provide a decreased resistance to withdrawal of said male contact terminal from said female terminal when withdrawal is at an off-angle relative to said central axis. 
     
     
       19. A terminal as set forth in claim 18 wherein said fourth ramped surface is angled with respect to said central axis at an angle within the range of 25°-40°. 
     
     
       20. A terminal as set forth in claim 18 wherein said fourth ramped surface is angled with respect to said central axis at an angle of about 33°-34°.